package 美团;

public class _64_最小路径和 {
    public int minPathSum(int[][] grid) {
        if (grid == null || grid.length == 0 || grid[0] == null || grid[0].length == 0) return 0;
        int minStep = grid[0][0];

        int[][] dp = new int[grid.length][grid[0].length];
        dp[0][0] = grid[0][0];
        for (int i = 1; i < grid.length; i++) {
            dp[i][0] = grid[i][0] + dp[i - 1][0];
        }

        for (int i = 1; i < grid[0].length; i++) {
            dp[0][i] = dp[0][i - 1] +grid[0][i];
        }

        for (int i = 1; i < grid.length; i++) {
            for (int j = 1; j < grid[0].length; j++) {
                dp[i][j] = Math.min(dp[i - 1][j], dp[i][j - 1]) + grid[i][j];
                minStep = Math.min(dp[i][j], minStep);
            }
        }
        return dp[grid.length][grid[0].length];
    }
}
